Fluid pump flow bypass control



J KNOWLES ET AL 3,356,034

FLUID PUMP FLOW BYPASS CONTROL Dec. 5, 1967 2 Sheets-Sheeti Filed Dec. 28, 1965 INVENTORJ. If

uzimes awZes, Mafia J, KNOWLES ET AL 3,356,034

Dec. 5, 1967 FLUID PUMP FLOW BYPASS CONTROL 2 Sheets-Sheet 2 Filed Dec. 28, 1965 INVENTORS,

Lrames Knowles, BY Rickard 2/7047! United States Patent '0 3,356,034 FLUID PUMP FLOW BYPASS CONTROL James Knowles, Bloomfield Hills, and Richard D. Moan, Dearborn Heights, Mich, assignors to Ford Motor Company, Dearhorn, Mich., a corporation of Delaware Filed Dec. 28, 1965, Ser. No. 516,998 Claims. (Cl. 103-97) ABSTRACT OF THE DISCLOSURE An air turbine pump having a bladed rotor cooperating with a bladeless stator containing an air darn that deflects the pressurized air into an outlet. The dam contains an air bypass opening that is closed by a gate that is spring biased to an open position and movable to a closed position by an engine oil pressure actuated servo. An air output pressure controlled diaphragm controlled supply and vent of oil pressure to the servo.

This invention relates, in general, to a fluid pump con trol. More particularly, it relates to an air compressor of the centrifugal type having means to bypass the high pressure discharge air back to the pump inlet above a predetermined pump speed.

Present day motor vehicles are being equipped with engine secondary air injection manifolds or similar devices to supply additional air to the engine exhaust system at all engine speeds so that any unburned hydrocarbons and other harmful elements that exist in the exhaust gases can be converted to less harmful forms before entering the atmosphere. This secondary source of air is generally supplied independently of the primary air intake system, and by an air compressor that generally is mounted on the engine as an accessory and driven at from two to three times engine crankshaft speed.

In substantially all'cases, the air pump is rotated at all engine speeds, and therefore consumes a considerable amount of useful engine output horsepower at the higher engine speeds when there is less need for additional air. It is a primary purpose of the invention, therefore, to provide a control for an air pump that is effective at higher engine speeds to bypass air from the outlet of the pump back to the inlet, and thereby reduce considerably the load on the pump and the horsepower required to drive the pump. This results in a substantial saving of useful horsepower and a greater engine operating efficiency.

One of the objects of the invention, therefore, is to provide a fluid pump control that at times bypasses fluid I from the high pressure side of the pump to the low pressure side. v Another object of the invention is to provide a centrifugal air pump h-aving cooperating rotor and stator members, the stator member having a fluid inlet and outlet and a control normally blocking communication therebetween in one direction of flow, the control being operable at times to permit a flow of air from the high to the low pressure side of the pump.

A further object of the invention is to provide an air compressor or pump with a fluid bypass that is operable at higher pump speeds to reduce the load on the pump and therefore the horsepower required to drive the pump. A still further object of the invention is to provide a centrifugal air pump with an air bypass control consisting of a gate movable into and out of the stator chamber of the pump to control communication between the high and low pressure sides of the pump; the gate being movable in response to movement of a valve that is differentially controlled by engine oil pressure and pump air discharge pressure operatively acting on opposite ends in a 3,356,3 1 Patented Dec. 5, 1967 manner such that at a predetermined air pressure, the gate will be withdrawn to permit a bypass of air, and the gate will remain withdrawn until the pump outlet pressure has dropped to a low value.

Another object of the invention is to provide an air pump bypass control of the type described that effects a quick bypass of the air when called for, and delays a return of the pump to its normal operation until the pump outlet pressure has decayed to a fairly low value.

Other objects, features and advantages of the invention will become apparent upon reference to the succeeding, detailed description thereof, and to the drawings illustrating the preferred embodiment thereof; wherein,

FIGURES 1 and 2 show, schematically, cross-sectional views of a fluid pump and a bypass control embodying the invention; and

' FIGURE 3 is a cross-sectional view taken on a plane indicated by and viewed in the direction of arrows 3-3 of FIGURE 1.

FIGURE 1 shows an air pump or compressor 10 of the centrifugal type. It includes a semi-toroidal driving shell or casing 12 that is welded or otherwise secured to one side of a V-type drive pulley 14. The pulley would have a speed-up belt drive type connection (not shown) to the engine crankshaft, and is fixed on a sleeve 16. The sleeve is rotatably mounted on a stationary shaft 18 by a pair of spaced annular ball bearing units 20 and 22. The ends of the sleeve are suitably sealed as shown.

Shell 12 supports a number of circumferentially spaced impeller or pump blades 24 to define a rotor member 26. Blades 24 are substantially dish-shaped in cross section, and cooperate with and face a semi-toroidal shaped cavity 28 defined by a stationary casing 30. The casing constitutes a stator member 32, and is hollow and bladeless. The stator has an air inlet opening 34 and a fluid discharge outlet 36 located on opposite circumferential sides of a narrow block seal or fluid abutment 38. The block seal normally prevents direct communication between the air inlet and outlet as blades 24 pass over the face seal portion 40 in a known manner. Stator 32 has a hub 42 fixedly secured to shaft 18, the shaft being threaded or otherwise secured in a stationary housing portion 44.

The axial spaces 46 and 48 between the outer and inner radial portions of the pump and stator casings are sealed by a pair of elastomeric rings 50 and 52. These rings are cemented or bonded in a suitable manner to extensions 54 and 56, respectively, of stator 32. They cooperate with external annular flanges or lips 58 and 60 provided, respectively, on the radially outward portion of impeller shell 12 and the inner hub portion of pulley 14. During initial rotation of impeller shell 12, each lip 58 and 60 will cut its own path into the respective elastomeric ring 50 and 52 to form an effective seal against leakage. Labyrinthian passages 62 and 64 formed by the shell extensions also minimize circumferential leakage.

In operation, as thus far described, rotation of rotor 26 by pulley 14, at say three times crankshaft speed, for example, causes air to be drawn in through inlet 34 into the spaces (not shown) between blades 24. The air is then centrifuged outwardly and forwardly into the stator cavity 28, where it is redirected back into the rotor blade cavities to impart additional energy to the blades. This continuing cycling imparts a helical spiral motion to the air, causing it to flow around the toroidal circuit until it reaches the block seal member 38, at which point it is diverted into the outlet 36 under pressure.

Turning to the invention, the block seal member 38 is shown as having a circumferentially extending through port or passage 66, which in this case is shown as being rectangular, although it will be clear that it could be of other suitable shapes. Flow of fluid or air from outlet 36 back to inlet 34 through passage 66 is controlled by a slide gate 68 that is movable in a direction substantially at right angles to passage 66. The movement of the gate is controlled by a fluid pressure actuated mechanism indicated schematically to the left of pump 10' in FIGURE 1.

More specifically, gate 68 is fixed to the shaft 70 of an actuator 72 having an enlarged end 74 slidably and sealingly mounted in the bore 76 of a valve body 78. The actuator is biased against one end of the bore by a spring 80 to withdraw gate 68 from passage 66. Gate 68 is moved across passage 66 upon admission of fluid under pressure to the end of the bore 76 through a line 82 Line 82 is connected alternately to a source of fluid under pressure in a line 84, or to a sump (not shown) through a drain line 86. The line 84 in this instance is connected to the conventional engine oil pump discharge line, and, therefore, contains oil normally at a pressure that will vary between 35 and 55 p.s.i., for example.

The flow of fluid to or drain from line 62 is controlled by the movement of a spool valve 88 having spaced lands 90 and 92 interconnected by a reduced neck portion 94. The valve is slidably mounted in the valve body 78, and is movable between the positions shown in FIG- URES 1 and 2. The valve is biased to the FIGURE 1 position by a spring 96, and has a central bore 93 connecting the annular fluid chamber 100 to the end of the valve. In the FIGURE 1 position, engine oil pressure acts behind the valve to aid spring 96 in maintaining the valve in the position shown so that oil under pressure can flow through line 82 to act on the gate actuator 72 and move the gate 68 to the position shown blocking passage 66.

The valve is moved to the FIGURE 2 position upon a rise in the pump discharge pressure suflicient to move a diaphragm type servo 102 connected to the valve. The servo consists of a housing 104 divided into fluid chambers 106 and 108 by an annular diaphragm 110. The diaphragm extends between the housing and an annular flange 112 fixed to a stem 114 on valve 88. Chamber 106 is connected to a branch line 116 of air pump outlet 36, and chamber 108 is vented to exhaust through a drain line 118. The common drain passage 120 is also connected to the gate actuator spring chamber 122.

In operation, when the engine that drives the air pump is rotating at low speeds, the pump output pressure in line 116 will be insufficient to overcome the force of spring 96, and the control system parts will be as shown in FIGURE 1. Engine oil pressure will flow through the valve central bore 98 into the chamber 124 containing spring 96 to maintain the valve in this position. The oil will also flow into line 82 and against the gate actuator 72 to move it against the force of spring 80 and position the gate 68 as shown to block flow through pump block seal passage 66.

Assume now the engine speed increases, which causes a corresponding increase in the pump outlet pressure. When this pressure reaches a predetermined level of say, p.s.i., for example, indicating a pump speed of say, 6000 rpm, for example, the air pressure is sufficient to move the valve 88 to the right against the force of spring 96 and the engine oil pressure to the FIGURE 2 position. This immediately cracks open the chamber 100 to drain line 86, and the oil pressure begins to drop. A resultant quick rightward movement of the valve occurs, and the oil pressure in line 82 drops to zero. Spring 80 now quickly strokes the gate actuator 72 to the left and thus moves gate 68 out of passage 66 to permit a bypass of air from the high pressure outlet side 36 of pump to the low pressure inlet side 34. The air pressure, therefore, immediately decays and unloads the pump so that considerably less horsepower now is required to drive it.

Since the only force acting on valve 88 to oppose the air pressure is the spring 96, the air pressure will continue to drop until it reaches a low value, such as, for example, .5 p.s.i. This pressure point will be determined, of course, by the value of the spring chosen. At the moment the spring force becomes greater than the air pressure, the

valve again will move to the left to the FIGURE 1 position and permit engine oil pressure to act behind the valve to maintain the valve in the FIGURE 1 position. Simultaneously oil under pressure is supplied to the gate actuator 72 to move it again against the force of its spring to the FIGURE 1 position, blocking the pump passage 66.

From the foregoing, therefore, it will be seen that the invention provides a bypass control for a centrifugal air pump that is responsive to engine or pump speed to bypass the output of the pump back to its inlet above a predetermined speed; and, that the control is actuated by fluid from the conventional engine oil pump, thereby eliminating the need for an additional source of fluid under pressure. It will thus be seen that the horsepower normally lost due to driving the air pump at high engine speeds is saved, and, therefore, results in a greater engine operating efliciency.

While the invention has been illustrated in its preferred embodiment in the figures, it will be clear to those skilled in the arts to which the invention pertains that many changes and modifications may be made thereto without departing from the scope of the invention. For example, while a block seal member is shown between the inlet and outlet, it will be clear that it could be eliminated if desired without departing from the scope of the invention, since the gate would serve substantially the same function by extending across the width of the stator cavity.

We claim:

1. A centrifugal pump having a bladed rotor member, a stator member cooperating therewith to define an annular fluid flow chamber therebetween, said stator member having a fluid inlet and outlet to said chamber, a source of fluid connected to said inlet, first conduit means connecting said inlet and outlet, fluid bypass control means movable into said conduit means to block flow from said outlet to said inlet while permitting flow from said inlet to said outlet and movable out of said conduit means to a bypass position permitting flow from said inlet to said outlet and back to said inlet, and means for controlling the movement of said bypass control means, said latter means including means biasing said control means to a fluid bypass permitting position essentially out of said conduit means, a second source of fluid under pressure, second conduit means operatively connecting said second source to said control means to act thereon to move said control means to a bypass blocking position into said first named conduit means, and means for controlling flow through said second conduit means.

2. A fluid pump as in claim 1, said last-mentioned means comprising a valve movable in a second conduit closing direction by fluid outlet pressure operatively acting thereon, and further means biasing said valve in the opposite second conduit flow permitting direction.

3. A fluid pump as in claim 1, said second source being operatively rotatable with said rotor member and varying in pressure as a function of the speed of said rotor member.

4. A fluid pump as in claim 1, said bypass control means including a gate movable across said stator member chamber portion circumferentially between said inlet and outlet.

5. A fluid pump as in claim 1, said stator member having a fluid abutment between said inlet and outlet, said first conduit means comprising a passage through said abutment, said bypass control including a gate slidable in said abutment across said passage.

6. A fluid pump as in claim 2, said second source varying in pressure as a function of the speed of said rotor member, said further means including means connecting fluid under pressure from said second source to act on said valve.

7. A fluid pump as in claim 2, said further means including means connecting fluid under pressure from said second source to act on said valve.

8. pump as in claim 2, including a diaphragm operatively connected to said valve and acted upon by the fluid at said outlet to move said valve in said second conduit closing direction.

9. A fluid pump as in claim 3, said valve being m'ovable from a first position blocking the connection between said source and said control means while connecting the fluid acting on said control means to a vent line to a second position blocking said vent line and connecting said source and control means,

10. A fluid pump as in claim 9, said valve having means connecting the fluid at said control means at all times to one end of said valve for biasing said valve at times to its second position, said valve when moved to its first position connecting said latter means to said drain line.

References Cited UNITED STATES PATENTS Becht 230-114 Bower 103-97 Kenney 103-97 Torell 230-114 Sanborn et a1. 103-96 Worst 103-96 10 DONLEY J. STOCKING, Primary Examiner.

HENRY F. RADUAZO, Examiner. 

1. A CENTRIFUGAL PUMP HAVING A BLADED ROTOR MEMBER, A STATOR MEMBER COOPERATING THEREWITH TO DEFINE AN ANNULAR FLUID FLOW CHAMBER THEREBETWEEN, SAID STATOR MEMBER HAVING A FLUID INLET AND OUTLET TO SAID CHAMBER, A SOURCE OF FLUID CONNECTED TO SAID INLET, FIRST CONDUIT MEANS CONNECTING SAID INLET AND OUTLET, FLUID BYPASS CONTROL MEANS MOVABLE SAID CONDUIT MEANS TO BLOCK FLOW FROM SAID OUTLET TO SAID INLET WHILE PERMITTING FLOW FROM SAID INLET TO SAID OUTLET AND MOVABLE OUT OF SAID CONDUIT MEANS TO A BYPASS PORTION PERMITTING FLOW FROM SAID INLET TO SAID OUTLET AND BACK TO SAID INLET, AND MEANS FOR CONTROLLING THE MOVEMENT OF SAID BYPASS CONTROL MEANS, SAID LATTER MEANS INCLUDING MEANS BIASING AID CONTROL MEANS TO A FLUID PYPASS PERMITTING POSITION ESSENTIALLY OUT OF SAID CONDUIT MEANS, A SECOND SOURCE OF FLUID UNDER PRESSURE, SECOND CONDUIT MEANS OPERATIVELY CONNECTING SAID SECOND SOURCE TO SAID CONTROL MEANS TO ACT THEREON TO MOVE SAID CONTROL MEANS TO A BYPASS BLOCKING POSITION INTO SAID FIRST NAMED CONDUIT MEANS, AND MEANS FOR CONTROLLING FLOW THROUGH SAID SECOND CONDUIT MEANS. 